1. Field of the Invention
The present invention relates to a method of converting a device-dependent image signal produced by a color scanner (hereinafter referred to as “scanner”), a digital camera, etc., into a device-independent image signal, a method of determining an original color in a color reproduction range of a color image that is recorded on a color reversal film, and an apparatus for converting a device-dependent image signal into a device-independent image signal.
2. Description of the Related Art
For image processing, it has heretofore been customary to convert a device-dependent image signal produced by a scanner, which is an image input device, into a density value on a densitometer or an equivalent neutral density as disclosed in Japanese laid-open patent publication No. 6-237373 and Japanese laid-open patent publication No. 6-261208, and process an image signal represented by the density value or the equivalent neutral density, i.e., a density-based image signal, for sharpness, set-up, or color correction processing.
In recent years, there has been established a standard color management technique for converting a device-dependent image signal produced by a scanner, a digital camera, etc., which is an image input device, into a device-independent image signal representing calorimetric values X, Y, Z or L*, a*, b*, processing the device-independent image signal, and then converting the processed device-independent image signal into a device-dependent image signal for use by a printing press, a printer, or a display monitor.
However, the image processing process which processes the device-independent image signal based on the colorimetric values fails to utilize the image processing technique that uses density-based image signals as conventional image processing resources.